1. Overview of Common Obstructive Uropathy in Childhood
DR RM AKUSE
Consultant Paediatric Nephrologist,
Ahmadu Bello University Teaching Hospital Zaria

2. DEFINITION
Obstructive uropathy(OU) is a condition in which the flow of urine is blocked along the urinary tract.
The hindrance may be structural or functional.
if left untreated can lead to injury to kidney(s) and renal failure.

3. WHY WORRY? Cause of morbidity and mortality in children
– CKD, HYPERTENSION, UTI
UPTH ( ), 20 CHILDREN
HYPERTENSION- 50%
RENAL FAILURE- 30%
DEATH - 35%
Accounted for 16.5% of all pediatric renal transplants in 1997

4. Potential killer

5. RENAL FAILURE DUE TO OU 30-70% of all End stage renal disease (ESRD)
NIGERIA
UPTH- 30%
UBTH - (9.6%)
CALABAR – 6.7%
OAUTH- 8%

6. Types Can occur in any part of the urinary system,
In children often congenital
Associated congenital abnormalites
CLASSIFICATION
Congenital/Acquired
Acute/Chronic
Anatomical- level of obstruction
Unilateral/Bilateral

7. Types KIDNEY Ureteropelvic junction (UPJ) obstruction URETER
Intraluminal = kidney stones, blood clots, papillae sloughing, scarring
Extraluminal - enlarged lymph nodes,
enlarged uterus (haematocolpos)
cancer/tumors,
strictures,
trauma

8. Types BLADDER Neurogenic Stones
Tumors or masses around the bladder neck or urethra
Scarring
Retroperitoneal fibrosis
URETHRA
Posterior and anterior urethral valve
Atresia
Tumors or masses
Phimosis
Meatal Stenosis – post circumcision

9. Common causes Congenital Posterior Urethral Valve (PUV) obstruction
Pelvi-Ureteric junction
Acquired
Calculi
Post traumatic
Post inflammatory strictures
Meatal stenosis
Associated anomalies
Dysplastic kidneys
Imperforate anus
Vertebral malformations
Prune belly syndrome

10. Ardissino et al (2003) OU cause of ESRD in 27.1% of pediatric patients
COMMONEST TYPES
Posterior urethral valves (23.8%).
Ureteropelvic junction (UPJ) obstruction= 3.6%,
Obstructive megaureter 3.5%,
some form of urethral hypoplasia/atresia 2.3%,
ureterocele 1.7%,
Other complex uropathies accounted for 5.9%.

11. UPTH – CAUSES OF OU (1997-2002) (n=20)
Post urethral Valve -16 (80%),
bladder calculi -2 (10%),
bladder rhabdomyosarcoma - 1 (5%)
urethral stenosis - 1 (5%)

12. PATHOPHYSIOLOGY
MECHANICAL DAMAGE
RELEASE OF BIOCHEMICAL MEDIATORS
CELLULAR INFILTRATES
FOETAL URINE FLOW IMPAIRMENT

13. MECHANICAL DAMAGE INCREASED INTRATUBULAR PRESSURE LOCAL ISCHEMIA
SIGNIFICANT LOSS OF FUNCTIONAL RENAL PARENCHYMA
SECONDARY REFLUX
SUPERIMPOSED UTI.

14. RELEASE OF BIOCHEMICAL MEDIATORS
prostaglandins,
thromboxane [A.sub.2]),
angiotensin II,
atrial natriuretic peptide,
nitric oxide, endothelin,
platelet activating factor,
nuclear factor kappa B (NF-[kappa]B),
transforming growth factor-beta (TGF-[beta]

15. CELLULAR INFILTRATES Macrophages, T-lymphocytes, and fibroblasts
glomerular damage,= albuminuria
tubular damage= elevated microglobulin alpha-1.
tubulointerstitium, - Most damage - Fiborsis

16. FOETAL URINE FLOW IMPAIRMENT
Causes deregulation of renal precursor cell turnover and expression of growth factor/survival and transcription factor genes.
Renal dysplasia

17. END RESULT HYDRONEPHROSIS, HYDROURETERS, HYPERTROPHIC BLADDER
BIOCHEMICAL ABNORMALITIES
sometimes type 1 renal tubular acidosis (reduced distal hydrogen secretion)
RENAL DYSPLASIA -undifferentiated and metaplastic tissues.
OBSTRUCTIVE NEPHROPATHY – bilateral,
unilateral

18. Clinical features Consider OU in patients with any of the following:
Diminished or absent urine output
Unexplained renal insufficiency
Pain that suggests distension in the urinary tract
oliguria or anuria alternating with polyuria

19. Clinical features Fever Dysuria
Problems with passing urine – incontinence, hesitancy, increased frequency
Poor urinary stream
Dribbling
Symptoms associated with primary disease

20. INVESTIGATIONS URINALYSIS may be normal
Abnormal - casts, WBCs, RBCs, albuminuria
Urine MCS
Urea, electrolytes, creatinine
FBC and differential.
IMAGING

21. Abdominal ultrasonography
Detection of hydronephrosis.
Follow up of hydronephrosis
false-negative results-
if obstruction is early,
if obstruction is mild
if retroperitoneal fibrosis or tumour encases the collecting system
preventing dilation
of the ureter.

22. Voiding cystourethrography (VCUG)
Displays anatomy of BLADDER NECK and URETHRA
Volume of urine left in the bladder after voiding
Vesicoureteral reflux,

23. Voiding cystourethrogram
posterior urethral valves
associated reflux (Grade V).

24. IVU USEFUL when CT cannot identify the level of obstructive uropathy
when acute obstructive uropathy is thought to be caused by calculi, sloughed papilla, or a blood clot
 Must have some renal function
Allergic reactions may occur
ANTEGRADE OR RETROGRADE PYELOGRAPHY

25. Antegrade pyelogram. stricture of distal ureter in
patient with moderate hydroureteronephrosis.

26. CT SCAN/MRI
CT SCAN- Used when obstruction cannot be shown by ultrasonography or IVU.
NOTE
ultrasonography and CT may not be able to differentiate hydronephrosis from multiple renal or parapelvic cysts.
MRI (with or without contrast).
used when avoiding ionizing radiation is important (eg, in young children).
as accurate as ultrasonography or CT.

27. Radionuclide scans Don’t use contrast agents Can determine perfusion
Identifies functional renal parenchyma
BUT cannot detect specific areas of obstruction
mainly used TOGETHER WITH diuresis renography to evaluate hydronephrosis without apparent obstruction.

28. Diuretic renography
Frusemide given before i.v injection of radiopharmaceutical (Tc 99m DPTA or MAG 3) or IVU).
Note- Must have enough renal function to respond to the diuretic.
Rate of washout of radionuclide (or contrast agent) is measured
Rapid washout - dilated non-obstructed system.
Delayed washout - obstructed pattern
Indeterminate - Washout between 1.5 and 20 minutes
False-positive and false-negative are common

29. LEFT: complete obstruction of one kidney (upper graph) partial obstruction of other kidney. RIGHT: Discrepancy in function but no evidence of obstruction

30. Foetal urinary electrolytes
normal foetal kidney makes hypotonic urine
foetal urinary biochemical markers most useful after 20 weeks' gestation
Reliability varies
foetal urinary sodium <100 mEq/L and
β-2 microglobulin -more appropriate predictor of postnatal serum creatinine in the foetus

31. INTERPRETATION
A dilated renal collecting system may not mean a true obstruction.
HYDRONEPHROSIS
must distinguish whether it secondary to an ongoing obstruction or secondary to a prior obstructive event that occurred and resolved antenatally.
THIS AFFECTS MANAGEMENT

32. MANAGEMENT
A challenge for paediatricians and urologists is to diagnose and intervene appropriately for problems
without overreacting to variants of normal.

33. MANAGEMENT GOALS Relieve obstruction – antenatal/Postnatal
Maximize renal function
Maintain normal bladder function
Minimize morbidity
Prevent iatrogenic problems

34. COMPLICATIONS CHRONIC KIDNEY DISEASE, ESRF UTI – Chronic or recurrent
BLADDER PROBLEMS- incontinence, retention
CALCULI – Renal or uretal
Complications due to long-term catheter use

35. PROGNOSIS Duration Specific nature of the blockage, Other factors
-Financial constraints
- Availability of diagnostic facilities
equipment drugs

36. Posterior urethral valve (PUV)
Commonest cause OU in children
Occurs sporadically but familial cases have been reported
Cause -obstructing membrane in lumen of the posterior (prostatic) urethra.

37. CLINCAL FEATURES broad spectrum of clinical severity
The most severe forms do not survive in utero,
Mildest forms may go undetected.
Antenatally
detected on routine foetal ultrasonography,
– hydronephrosis,
renal parenchymal echogenicity, renal cysts

38. PRENATAL ULTRASOUND OF FETUS WITH PUV
renal dysplasia
Severe hydronephrosis,
parenchymal thinning, increased echogenecity of parenchyma.
Sagittal view of upper pole of kidney with renal cyst.

39. Ultrasound of bladder of patient with PUV
Full bladder with thickened wall and dilated ureters posterior to the bladder (black arrows).
Prenatal ultrasound with dilated posterior urethra and dilated bladder (“keyhole” sign).

40. POSTNATAL
age at presentation- BIRTH -13 YEARS,
Poor urinary stream.
incontinence
recurrent UTIs.
Urinoma
Urinary ascites

41. MANAGEMENT - POSTNATALLY
ASSESS PATIENT
Treat Acute illness
Surgery - Ablation of valve
Urinary diversion -vesicostomy, cutaneous ureterostomy,
augmentation cystoplasty with later reconstruction.
Manage CKD
RENAL TRANSPLANT
FOLLOW UP - Check for persisting or increasing upper urinary tract dilatation, increasing serum creatinine, bladder problems

42. PRENATAL INTERVENTION
Uncertain whether antenatal diagnosis or treatment improves long-term renal outcome
Identify those who intervention may benefit using
gestational age,
amniotic volume,
Renal dysplasia - cortical cysts, increased echogenicity.
renal function - -urinary electrolytes, β-microglobulin levels
Karyotype

43. Foetal surgery continues to remain controversial.
normal outcomes can occur without intervention.
Indications
? for the carefully selected patient who has normal-appearing kidneys and normal urinary electrolytes with severe oligohydramnios
Surgery - vesicoamniotic shunts, valve ablation , bladder marsupialization

44. COMPLICATIONS of interventions
Shunt failure and declining appearance of fetal lungs kidney.
Chorioamnionitis,
Spontaneous ruptures of membrane,
amniotic fluid leak.
Premature labor with respiratory failure.
Fetal mortality rate – 33-43%.

45. POSTNATALLY
intervention may not change the prognosis of renal function
We must not give families unrealistic expectations that fetal surgery is the cure for obstructive uropathy or that the child will not need extensive follow-up after delivery.

46. Outcome BLADDER DYSFUNCTION
hyperreflexia, hypertonic, small capacity bladder, sphincter incompetence and/or myogenic failure.
End-stage renal disease –
Renal failure - in 19% to 64% diagnosed prenatally
in 25% to 40% diagnosed postnatally

47. CONCLUSION:
Advances in postnatal surgery and medical management have reduced the mortality in PUV
Earlier diagnosis by ultrasound,
Developments in surgical technique
Meticulous attention to neonatal care.

48. UPJ obstruction Intrinsic obstruction
hypoplastic adynamic ureteral segment at the UPJ
Extrinsic causes - aberrant vessels, kinks,
PAIN - abdominal or flank -worse with diuresis
hematuria following mild trauma,
chronic nausea, UTI.
DIURETIC RENOGRAPHY – may be delayed washout
Rx – Nil, surgery, Antibiotics

49. Uretervesical junction (UVJ) OBSTRUCTION
hydroureter + HYDRONEPHROSIS
NORMAL BLADDER
megaureter. - not necessarily obstructed.
mainly found incidentally on prenatal sonography,
Usually normal physical exam
UTI, hematuria,
abdominal pain or mass,
uremia.

50. Management Depends on presence of obstruction presence of reflux,
Continued surveillance
Patients with nonobstructed system often resolve spontaneously
antibiotic prophylaxis is recommended until a proper diagnosis can be made.
Surgery -

51. SURGERY increasing hydronephrosis on ultrasound,
decreasing renal function,
Recurrent infections
Persistent symptoms
Calculi
Careful follow up

52. The Future
? Development of molecular markers for diagnosis and progression
? Improve criteria to select patients for treatment
? improve prenatal treatment to improve bladder function,
? Better imaging techniques
???fetal magnetic resonance imaging to assist in differentiating PUV from other causes of severe hydronephrosis, eg, prune belly syndrome,
vesicoureteral reflux

53. Prevention need to improve the country's socioeconomic conditions
Need to improve health facilities
make medical facilities more available to children
prevent renal diseases that may lead to ESRF
Education at the community level

54. CONCLUSION OU – IMPORTANT CAUSE OF RENAL IMPAIRMENT
ADEQUATE MEASURES NEEDED TO PREVENT OR TREAT ESRF
RESOURCE CONSTRAINED COUNTRIES – SEVERAL CHALLENGES

56. REFERENCES
Anochie I, Eke F.Obstructive uropathy in childhood, as seen in University of Port Harcourt Teaching Hospital, Nigeria. Niger J Med Apr-Jun;13(2):136
Michael IO, Gabriel OE. Pattern of renal diseases in children in midwestern zone of Nigeria. Saudi J Kidney Dis Transpl Oct-Dec;14(4):
Nasir AA, Ameh EA, Abdur-Rahman LO, Adeniran JO, Abraham MK. Posterior urethral valve. World J Pediatr Aug;7(3): Epub 2011 Aug 7.
Etuk IS, Anah MU, Ochighs SO, Eyong M..Pattern of paediatric renal disease in inpatients in Calabar, Nigeria. TropDoct Oct;36(4):256.
Eke FU, Eke NN Renal disorders in children: a Nigerian study. PediatrNephrol Jun;8(3):383
Woolf AS; Thiruchelvam . Congenital obstructive uropathy: its origin and contribution to end-stage renal disease in children.Adv Ren Replace Ther.  2001; 8(3):157-63 
Obstetric uropathy . Considerations for the nephrology nurse. Nephrology Nursing Journal . March 2004
Ardissino et al 2003).
Nicholas Holmes, Michael R. Harrison, Laurence S. Baskin, Fetal Surgery for Posterior Urethral Valves: Long-Term Postnatal Outcomes
Obstructive uropathy - Overview
ROTH Karl S) ; KOO Harry P. ; SPOTTSWOOD Stephanie E. ; CHAN James C. M.Obstructive uropathy: An important cause of chronic renal failure in children
Congenital obstructive uropathy: its origin and contribution to end-stage renal disease in children. Adv Ren Replace Ther.  2001; 8(3):157-63 
N Eke, SN Elenwo. Obstructiveuropathy in childhood: A review Port Harcourt Medical Journal>Vol 1, No 3 (2007)
Casale AJ Early ureteral surgery for posterior urethral valves.
. Urol Clin North Am May;17(2):

57. Anochie I, Eke F.Obstructive uropathy in childhood, as seen in University of Port Harcourt Teaching Hospital, Nigeria. Niger J Med Apr-Jun;13(2):136
Michael IO, Gabriel OE. Pattern of renal diseases in children in midwestern zone of Nigeria. Saudi J Kidney Dis Transpl Oct-Dec;14(4):
Nasir AA, Ameh EA, Abdur-Rahman LO, Adeniran JO, Abraham MK. Posterior urethral valve. World J Pediatr Aug;7(3): Epub 2011 Aug 7.
Etuk IS, Anah MU, Ochighs SO, Eyong M..Pattern of paediatric renal disease in inpatients in Calabar, Nigeria. TropDoct Oct;36(4):256.
Eke FU, Eke NN Renal disorders in children: a Nigerian study. PediatrNephrol Jun;8(3):383 .
Woolf AS; Thiruchelvam . Congenital obstructive uropathy: its origin and contribution to end-stage renal disease in children.Adv Ren Replace Ther.  2001; 8(3):157-63 (
Obstructive uropathy: considerations for the nephrology nurse. : Nephrology Nursing Journal Publication Date: 01-MAR-04
Ardissino et al 2003).
Nicholas Holmes, Michael R. Harrison, Laurence S. Baskin,
Fetal Surgery for Posterior Urethral Valves: Long-Term Postnatal Outcomes
Obstructive uropathy - Overview

58. THANK YOU!